油菜根系固土拉力的原位测定研究*

 应用锚杆拉力计和自行设计的剪切箱对不同根系密度的油菜根系固土能力在10cm深度进行了原位测定。结果表明,当施加载荷达到35kN时，生长有油菜的土壤样方1（根系密度为111kg/m3）位移为380mm，生长有油菜的土壤样方2（根系密度为057kg/m3）位移为460mm，而裸土样方位移为497mm。土壤样方内根系密度越大，达到土壤样方与土体分离的特征点所需要施加的载荷就越大。土壤样方1的屈服拉力点为35kN, 抗拉极限点为40kN；而土壤样方2的屈服拉力点为31kN,抗拉极限点为35kN。该测定方法可以在水土保持上作为评价不同作物（植物）固土能力的有效参考手段。

Researches on In situ Measurement of theSoil Fixing Capability of Rape Roots

Experiments of in situ measuring the stabilization capability of soil by rape roots in 10cm depth with the anchor shank tensiometer and self designed shear box were conducted. The results showed that when a 35KN load was applied, the displacements of sample plot 1 (roots density =111 kg/m3), sample plot 2 (roots density =057kg/m3) and control plot reached 380mm, 460mm and 497mm, respectively. The higher the root density was in the sample plot, the more loads which made sample plot separate from bulk soil was required. The bending point F2 and plastic deformation point F3 of sample plot 1 were 35kN and 40kN, respectively; those of sample plot 2 were 31kN and 35kN. It is proposed that this is an appropriate method to evaluate the root function of different crops or plants in maintaining slope stability. 